Chemicals have been used for centuries to fight unwanted pests. The war against infestation of plants is a constant battle. Plant and agriculture producers try to eradicate insect species with chemicals. The nonaffected (resistant) individuals within a population are able to breed and thereby produce a new generation that is more resistant to the insecticide that was being used. Consequently, the dosage and frequency of application for that insecticide must be increased, or else something different must be used. Thus, there is a continued need to identify new methods of deterring pests from damaging plants and agricultural products.
Synthetic insecticides have found there way in to sources of water and animals that are consumed by humans such as undesirable residues of DDT, heptachlor, mirex, contaminating fish, water, and the soil. One benefit of using a natural plant insecticide is that many of them are biodegradable. Insecticides such as organo-phosphorus and carbamate esters are biodegradable, but many still manifested broad-spectrum toxicity, with a potential for poisoning nontarget insects, fish, wildlife, livestock, and humans. There are several natural (plant) insecticides that have been widely used such as rotenone and pyrethrin. Rotenone is a terpene; however, it is generally applied as a spray on fruits and row crops several times before harvesttime because the chemical residues do not linger for long periods of time. Thus, there is still a need to identify genetically engineered plants with increased resistance to predations by using genes or appropriate modifications in the plants.